Electrochemical reaction device and method of operating electrochemical reaction device

Abstract

An electrochemical reaction device includes: an electrochemical reaction structure including a cathode to reduce carbon dioxide to produce a carbon compound, an anode to oxidize water to produce oxygen, a diaphragm therebetween, a cathode flow path on the cathode, and an anode flow path on the anode; a first flow path through which a first fluid to the cathode flow path flows; a second flow path through which a second fluid to the anode flow path flows; a third flow path through which a third fluid from the cathode flow path flows; a fourth flow path through which a fourth fluid from the anode flow path flows; and a gas-liquid separator in or on the anode flow path and to separate a gas containing the oxygen from a fifth fluid containing the water and the oxygen through the anode flow path.

1 . An electrochemical reaction device comprising:
 an electrochemical reaction structure comprising
 a cathode having a reduction catalyst that promotes a reduction reaction of reducing carbon dioxide to produce a carbon compound, 
 an anode having an oxidation catalyst that promotes an oxidation reaction of oxidizing water to produce oxygen, 
 a diaphragm provided between the cathode and the anode, 
 a cathode flow path facing on the cathode, and 
 an anode flow path facing on the anode; 
   a first flow path through which a first fluid to be supplied to the cathode flow path flows, the first flow path being connected to an inlet of the cathode flow path, and the first fluid containing the carbon dioxide;   a second flow path through which a second fluid to be supplied to the anode flow path flows, the second flow path being connected to an inlet of the anode flow path, and the second fluid containing the water;   a third flow path through which a third fluid to be discharged from the cathode flow path flows, the third flow path being connected to an outlet of the cathode flow path, and the third fluid containing the carbon compound;   a fourth flow path through which a fourth fluid to be discharged from the anode flow path flows, the fourth flow path being connected to an outlet of the anode flow path, and the fourth fluid containing the water and the oxygen; and   a gas-liquid separator provided in the middle of the anode flow path or on the anode flow path, the gas-liquid separator being configured to process a fifth fluid that flows through the anode flow path and contains the water and the oxygen to separate a gas containing the oxygen from the fifth fluid.   
     
     
         2 . The electrochemical reaction device according to  claim 1 , further comprising:
 a second cathode flow path provided between the cathode and the diaphragm;   a fifth flow path thorough which a sixth fluid to be supplied to the second cathode flow path flows, the fifth flow path being connected to an inlet of the second cathode flow path, and the sixth fluid containing an electrolytic solution; and   a sixth flow path through which a seventh fluid to be discharged from the second cathode flow path flows, the sixth flow path being connected to an outlet of the second cathode flow path.   
     
     
         3 . The electrochemical reaction device according to  claim 1 , further comprising:
 a first current collector connected to the cathode; and   a second current collector connected to the anode,   wherein the first current collector and the second current collector are connected to a power source.   
     
     
         4 . The electrochemical reaction device according to  claim 1 , comprising:
 a plurality of the gas-liquid separators.   
     
     
         5 . The electrochemical reaction device according to  claim 1 ,
 wherein the gas-liquid separator is connected to the fourth flow path and is configured to process the fourth fluid from the fourth flow path to separate a gas containing the oxygen from the fourth fluid.   
     
     
         6 . The electrochemical reaction device according to  claim 1 , further comprising:
 a second gas-liquid separator configured to process the fourth fluid to separate a gas containing the oxygen from the fourth fluid; and   a seventh flow path through which the processed fourth fluid to be supplied from the second gas-liquid separator to the second flow path flows.   
     
     
         7 . The electrochemical reaction device according to  claim 1 , comprising:
 a plurality of the gas-liquid separators,   wherein the electrochemical reaction structure comprises a plurality of the anode flow paths,   wherein the plurality of the anode flow paths are connected in parallel,   wherein one of the plurality of the gas-liquid separators is provided on one of the plurality of the anode flow paths, and   wherein another one of the plurality of the gas-liquid separators is provided on another one of the plurality of the anode flow paths.   
     
     
         8 . The electrochemical reaction device according to  claim 1 , further comprising:
 a removing part provided in the gas-liquid separator and having at least one remover selected from the group consisting of an ion remover and a radical remover, the ion remover being configured to remove a metal ion from the fifth fluid, and the radical remover being configured to remove a hydroxyl radical from the fifth fluid.   
     
     
         9 . The electrochemical reaction device according to  claim 1 , further comprising:
 at least one detector selected from the group consisting of a pH detector and an ion impurity detector, the least one detector being connected to the gas-liquid separator, the pH detector being configured to detect a pH of the fifth fluid, and the ion impurity detector being configured to detect a concentration of an ion impurity in the fifth fluid.   
     
     
         10 . The electrochemical reaction device according to  claim 9 , further comprising:
 a pH adjusting part connected to the gas-liquid separator and configured to adjust the pH of the fifth fluid.   
     
     
         11 . The electrochemical reaction device according to  claim 1 , further comprising:
 a recovery part provided in the gas-liquid separator and configured to recover the oxidation catalyst from the fifth fluid.   
     
     
         12 . The electrochemical reaction device according to  claim 1 , comprising:
 a stack comprising a plurality of the electrochemical reaction structures, the plurality of the electrochemical reaction structures being stacked,   wherein the gas-liquid separator is provided in the middle of each of a plurality of the anode flow paths of the plurality of the electrochemical reaction structures.   
     
     
         13 . The electrochemical reaction device according to  claim 1 , comprising:
 a stack comprising a plurality of the electrochemical reaction structures which are stacked; and   a plurality of the gas-liquid separators,   wherein a plurality of the anode flow paths of the plurality of the electrochemical reaction structures are connected in parallel,   wherein one of the plurality of the gas-liquid separators is provided on one of the plurality of the anode flow paths, and   wherein another one of the plurality of the gas-liquid separators is provided on another one of the plurality of the anode flow paths.   
     
     
         14 . The electrochemical reaction device according to  claim 1 ,
 wherein the anode flow path includes:   a first anode flow path part facing on the anode, the first anode flow path part being connected to the inlet of the anode flow path;   a second anode flow path part facing on the anode, the second anode flow path part being connected to the outlet of the anode flow path;   an eighth flow path through which the fifth fluid to be supplied from the first anode flow path part to the gas-liquid separator flows; and   a ninth flow path through which the processed fifth fluid to be supplied from the gas-liquid separator to the second anode flow path part flows.   
     
     
         15 . A method of operating an electrochemical reaction device,
 the electrochemical reaction device comprising:   an electrochemical reaction structure comprising
 a cathode having a reduction catalyst that promotes a reduction reaction of reducing carbon dioxide to produce a carbon compound, 
 an anode having an oxidation catalyst that promotes an oxidation reaction of oxidizing water to produce oxygen, 
 a diaphragm provided between the cathode and the anode, 
 a cathode flow path facing on the cathode, and 
 an anode flow path facing on the anode; 
   a first flow path which through a first fluid to be supplied to the cathode flow path flows, the first flow path being connected to an inlet of the cathode flow path, and the first fluid containing the carbon dioxide;   a second flow path through which a second fluid to be supplied to the anode flow path flows, the second flow path being connected to an inlet of the anode flow path, and the second fluid containing the water;   a third flow path through which a third fluid to be discharged from the cathode flow path flows, the third flow path being connected to an outlet of the cathode flow path, and the third fluid containing the carbon compound; and   a fourth flow path through which a fourth fluid to be discharged from the anode flow path flows, the fourth flow path being connected to an outlet of the anode flow path, and the fourth fluid containing the water and the oxygen, and   the method comprising:   supplying the first fluid to the cathode flow path, supplying the second fluid to the anode flow path, and supplying a current or a voltage to the electrochemical reaction structure, to reduce the carbon dioxide to produce the carbon compound on the cathode and to oxidize the water to produce the oxygen on the anode; and   processing a fifth fluid flowing through the anode flow path and containing the water and the oxygen to separate a gas containing the oxygen from the fifth fluid.   
     
     
         16 . The method according to  claim 15 , the electrochemical reaction device further comprising:
 a second cathode flow path provided between the cathode and the diaphragm;   a fifth flow path thorough which a sixth fluid to be supplied to the second cathode flow path flows, the fifth flow path being connected to an inlet of the second cathode flow path, and the sixth fluid containing an electrolytic solution; and   a sixth flow path through which a seventh fluid to be discharged from the second cathode flow path flows, the sixth flow path being connected to an outlet of the second cathode flow path.   
     
     
         17 . The method according to  claim 15 , the electrochemical reaction device further comprising:
 a first current collector connected to the cathode; and   a second current collector connected to the anode,   wherein the first current collector and the second current collector are connected to a power source.   
     
     
         18 . The method according to  claim 15 , the electrochemical reaction device comprising:
 a plurality of the gas-liquid separators.   
     
     
         19 . The method according to  claim 15 ,
 wherein the gas-liquid separator is connected to the fourth flow path and processes the fourth fluid from the fourth flow path to separate a gas containing the oxygen from the fourth fluid.   
     
     
         20 . The method according to  claim 1 , the electrochemical reaction device further comprising:
 a second gas-liquid separator configured to process the fourth fluid to separate a gas containing the oxygen from the fourth fluid; and   a seventh flow path through which the processed fourth fluid to be supplied from the second gas-liquid separator to the second flow path flows.